What’s the News: When vampire bats bite their victims, their saliva releases an enzyme called desmoteplase, or DSPA, into the bloodstream, which causes blood to flow more readily. Several years ago, scientists realized that the same enzyme that gives bats more blood for their bite may also help stroke victims by breaking down blood clots. Dubbed Draculin, this blood-clot-bashing drug has now entered a phase 2 study: In hospitals across the country, scientists are currently comparing Draculin with traditional anticoagulants to see if it increases the three-hour window doctors have to treat post-stroke blood clots. “This is one of the studies that actually extends that window up to 9 hours,” says lead researcher Michel Torbey. “We’re hoping the bat saliva, in itself, dissolves the clot with lower risk of bleeding in the brain afterwards.”What’s the Context:

The most common blood-clot breaker right now is called tissue plasminogen activator, or tPA. The problem is that if it isn’t administered to a patient within three hours of a stroke, it does more harm than good. Because a majority of patients don’t seek medical help fast enough, “tPA is used in a very small percentage of sufferers.”

If effective, Draculin would help prevent ischemic strokes, a type of stroke caused when blood clots block blood flow to the brain. It accounts for 87% of the 795,000 strokes Americans have each year (the other being hemorrhagic strokes, caused when blood vessels burst).